Clamp on amp meter reads cord

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GG

Senior Member
Location
Ft.Worth, T.X.
Someone told me they have a meter where they work with computers that reads the amp draw on a cord. Does anyone know if such a meter exists and how it works? A "normal" meter like mine would read 0 amps if you tried to take an amp reading on say a microwave cord.
 

480sparky

Senior Member
Location
Iowegia
It reads zero because you are taking an amp reading of not only the current flowing through the hot (ungrounded) conductor, but the equal but opposite flow through the neutral (grounded) conductor. They will cancel each other out.

You need to seperate them to get an accurate reading.

Lineseprator.jpg
 
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LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
There are also plug-in devices that show power usage.

It reads zero because you are taking an amp reading of not only the current flowing through the hot (ungrounded) conductor, but the equal but opposite flow through the neutral (grounded) conductor. They will cancel each other out.
Which shows why all conductors of a circuit need to be run together when in metal raceways.
 

GG

Senior Member
Location
Ft.Worth, T.X.
It reads zero because you are taking an amp reading of not only the current flowing through the hot (ungrounded) conductor, but the equal but opposite flow through the neutral (grounded) conductor. They will cancel each other out.

You need to seperate them to get an accurate reading.

Lineseprator.jpg
I realize this and why it reads 0. This person said they make a clamp on meter that will read the amperage by somehow cancelling one of the lines out. I have no need for one, I just wanted to know if such a meter existed and how it was able to cancel 1 of the legs out to get an amp reading,
 

S'mise

Senior Member
Location
Michigan
cheapskates think alike

cheapskates think alike

I'm with with Jim. You can make one up that does the exact same thing, in the amount of time it takes to open the box and separate the wires. The only advantage with the model with the square holes, might be it would hold your clamp-on more upright. ?
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Lineseprator.jpg


I have one like this, but it says Amp Probe on it, it came with my Amp Probe, but I have seen them around at one of the Big Box Stores, wasn't to expensive.
I wonder if the instructions specify to be used only with Amprobe meters, meaning that UL prohibits its use with any others? ;)
 
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